<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>按钮</button>
    <script>
        let btn=document.querySelector('button')
        let num=1
        let key 
        btn.addEventListener('click',function(){
           if(key===false){
            return
           }
           key=false
           num++
        //   设置定时器 不到时间 让key为false 不执行  等待时间过后再变为true
           setTimeout(function(){
            console.log(`节流${num}`);
            key=true
           },3000)
        })
    </script>
</body>
</html>